Power tool



Aug. 27, 1957 E. F. LUsHANsKY. JR

POWER TOOL 2 Sheets-SheetI 1 Filed April l5, 1955 Dbl ` ATTOPNEKY E. F. LUSHANSKY. JR

Aug. 27, 1957 POWER TOOL.

2 Sheets-Sheet 2 Filed Aprll 13, 1955 a United States Patent O POWER TOOL Edward F. Lushansky, Jr., Waterbury, Conn.

Application April 13, 1955, Serial No. 501,613

Claims. (Cl.` 121-3) This invention relates to a power tool and more specifically to a portable, pneumatically-operated, reciprocating hand tool. ln particularly this invention is directed to a power-operated, reciprocating le.

Many mechanical operations require a tiling step. This step is particularly necessary in the repair of automobile fenders or other body parts thereof, which are bent, twisted, or otherwise damaged. In straightening such bends or otherwise damaged portions, slight indentations or rough spots are produced which necessitate the performance of a tiling operation in order to smooth out the repaired area.

Heretofore, such tiling operations were performed by hand. However, such a manual tiling procedure was slow, laborious and diicult. In order to overcome the obvious disadvantages of the tedious hand filing operations, efforts have been made to produce a power-operated tool to` accomplish the task.

While several known power-operated filing tools have been developed, they have not received any prominence in the art in that certain definite disadvantages were inherent in such tools. Chiefly among these disadvantages were that they were relatively expensive and complex and difficult to handle. Another disadvantage of the prior known devices was that they had a relatively short reciproeating stroke which was undesirable. As a result these known power-operated files failed to gain wide usage, and consequently, the method of hand tiling is still greatly resorted to.

It is an object of the present invention to overcome the above diliculties and to provide for a power-operated, reciprocating, hand-held tile which is relatively simple in construction, inexpensive to produce, and positive in operation.

Another object of this invention is to reduce the number of moving parts of a power-operated le to a minimum, thereby eliminating much of the bulk and cornplexity which was an inherent disadvantage in the prior known devices.

It is still a further object of this invention to provide a power-operated, reciprocating, filing tool which is pneumatically-operated and which transverses a power stroke of suiiicient length to carry out a desirable tiling operation.

These objects are accomplished by a tool consisting of a housing having a pneumatically-operated cylinder of substantially shorter length slidably mounted thereon so that it can reciprocate relative thereto, the desired working tool being connected to the cylinder to move therewith. To control the movement and direction of the cylinder, a fixed piston having a piston head is connected to a source of fluid pressure supply, the piston head being disposed within the cylinder to divide the latter into two chambers. Means cooperating with the piston to form a valve means automatically actuated by the cylinder directs fluid pressure alternately, first into one chamber and then into the other, each chamber having also means for alternately exhausting its respective ice chamber so that as fluid pressure is directed into one cylinder chamber, the other is being exhausted, thus causing the cylinder to reciprocate and to transverse the required power stroke.

A feature of this invention resides in the provision of a fixed piston having means for alternately directing fluid pressure to either side thereof, thereby causing the cylinder to reciprocate relative thereto.

Another feature of this invention resides in the provision of means cooperating with the lixed piston to alternately exhaust one side of the cylinder as the other side is supplied with uid pressure.

Another feature of this invention resides in the provision of a piston having a piston head forming a valve means which is automatically actuated by the cylinder to direct fluid pressure alternately to either side of the cylinder.

Another feature of this invention resides in the provision of exhaust means cooperating with the fixed piston and automatically actuated by the cylinder to alternately exhaust either side of the cylinder.

Another feature of this invention resides in the provision that the length of any desired power stroke can be readily had by predeterminately proportioning the length of the cylinder relative to the length of the housing.

Another feature of this invention resides in the provision of the power tools relative simplicity, and in its reduction of movable parts which renders it inexpensive to manufacture and positive in operation.

Other features and advantages will be apparent from the specification and claims when considered with the drawings in which:

Figure l is a vertical sectional view of the novel reciprocating pneumatically-operated hand tool illustrating the arrangement of parts during the forward stroke.

Fig. 2 is a plan sectional view of the device in the position illustrated in Fig. l taken along line 2-2 thereof.

Fig. 3 is a vertical sectional view illustrating the positioning of the parts for the return or backward stroke of the hand tool.

Fig. 4 is a partial plan sectional view taken along line 4-4 of Fig. 3 illustrating the alignment of the parts in the position shown in Fig. 3.

Fig. 5 is a sectional view taken along line 5-5 of Fig. 3.

In accordance with this invention the novel hand tool, herein illustrated, is in the form of a reciprocating power operated tile. While the tool may be suitably powered by hydraulic means and the like, the illustrated embodiment of the tool according to the invention is pneumatically operated. The tool 10 consists of an elongated frame or housing member 11 which is substantially C-shaped in cross section, the ends of the C-shaped housing being closed by end walls 12 and 13. A closed cylinder 14 having a substantially shorter length than that of the housing is slidably mounted within the housing so that it may reciprocate relative thereto. As shown in Fig. 5, the bottom portion of the cylinder is provided with spaced abutments or mounting portion 15 for connecting thereto a suitable working tool, herein illustrated as a iile 15, although any other suitable type of reciprocating tool may be attached thereto. Suitable fasteners, such as bolts 17, secure the iile 16 to the mounting portion 15 so that the former reciprocates `with the cylinder. Thus it will be noted that, since the file can be readily removed, various types of iiles may be detachably secured to the cylinder so that any desired filing operation may be performed. If desired, suitable handle means H are provided.

While the cylinder may be slidably mounted on the housing by any suitable means, the illustrated embodiment of the invention provides that the cylinder 14 be mounted thereon by means of ball bearings 18. This is accomplished by providing the opposite side walls 19 and 20 of the housing 1 1 with longitudinally extending channel ways 21 extending the length thereof, which cooperate with externally positioned channel ways 22V on the adjacent cylinder walls to secure therebetween a row of ball bearings 1S extending the length of the cylinder as shown in Fig. 2. In order to maintain the ball Vbearings confined within the cooperating channel ways 21 and 22, the end walls`23 and 24 of the cylinder Yare provided with flanges 23a and 24a so that the bearing rows 18 travel with the cylinder 14. In this manner, the cylinder 14 can be readily moved back and forth smoothly and easily without any binding effects between the housing and the cylinder.

Disposed between the end walls 12 and 13 of the housing 11 and mounted thereon in fixed relationship relative thereto is a fixed piston 25 consisting of a piston rod 26 and a piston head 26a, the latter being fixed intermediate the end portions of the piston rod 26. As illustrated in Figs. l to 4, the piston rod 26 extends through the end walls 23 and 24 of the cylinder so that the piston head 26a divides the cylinder into two chambers 27 and 23. It will be understood that the piston rod 26 extending through the end walls of the cylinder cooperates therewith to form a suitable seal so as to prevent any leak or loss of fluid pressure when the tool is in operation. To facilitate assembly and removal of the piston 25 from the cylinder, an end wall 24 of the cylinder is removably secured thereto by suitable fasteners 29.

According to this invention, the piston rod 26 comprises a hollow tube for receiving in sliding relationship relative thereto, a control rod 30 as will be hereinafter explained. As shown in Figs. 1 and 3, the piston rod 26 is provided with a longitudinally extending supply passageway 26!) which communicates with an opening 12a in the housing end wall 12 to which there is secured a nipple 31 for receiving a supply conduit 32 connecting with a source of fluid pressure supply, e. g. an air compressor or the like (not shown). The other end of the supply passageway 2617 connects with a vertical port 33 opening intermediate the ends of the piston rod, the port 33 communicating with the hollow interior portion of the rod in the vicinity of the piston head.

As shown in Figs. 2 and 4, the piston head is provided with spaced channel ways 34-34, 35-35 connecting with each of the chambers 27, 28, two such channel ways 34%34, 35-35 connecting with each chamber 27 and 28 respectively from opposite sides of the piston rod. Thus, as it will be more fully set forth, fluid pressure supplied from a suitable source (not shown) is directed to the cylinder 14 through conduit 32 and nipple 31, supply passageway 26h, and then alternately into either chamber 27 or 28 through its respective spaced channel Ways 34 or 35.

In order to control the passage of fluid pressure from the source of supply to either of the chambers alternately, there is provided, according to this invention a control rod 30 which isautomatically actuated by the cylinder 14 as it approaches the end or limit of its stroke. This rod 30 is mounted within the hollow portion of the piston rod 26 so as to be freely slidable therein, the right end of the rod 30 in the preferred embodiment being adapted to extend through the opening 13a as it is moved relative to the piston rod, as will be hereinafter described. Intermediate the end of the control rod and in the vicinity of the piston head, the rod 30 is provided with a pair of transverse feed channels 36 and 37 which are adapted to automatically connect the port 33 alternately with the pair of spaced channel ways 34-34, 35-35 of the piston head so that the fluid pressure is directed alternately into either chamber.

As shown in Figs. 1 and 2 in the initial or starting position, the transverse feed channel 36 connects the port 33 with the spaced channels 34-34 in the piston head 25a so that the fluid pressure owing through the supply passageway Zb is directed into chamber 27. The uid pressure building up in the chamber 27 forces the cylinder to move to the right. In this position, it will be noted that the transverse feed passage 37 'is out of communication with the port 33 and the spaced channels 35-35 are closed so that the pressure is directed through channels 34-34 and into the chamber 27.

In order to alternate the direction of fluid pressure, the control rod 30 has fixed thereto adjacent each end au actuating pin 38 which projects through a slotted opening 39 in the piston rod 26. Thus, as the cylinder 14 approaches the end limit of its stroke, the end wall 23 of the cylinder engages the actuating pin 38 causing the control rod to be moved to the right as shown in Fig. 3. In doing so the transverse feed channel 36 is moved out of cornmunication with the intake port 33 to close olf the channels 34-34 feeding into the chamber 27. At this point, as shown in Fig. 4, the other transverse feed channel 37 is moved to a position over the port 33 to connect the latter to the spaced channels 35-35 so that the fluid pressure is directed in the opposite direction to fill the chamber 28 forcing the cylinder rearwardly or to the left.

However, to move the cylinders in either direction, it is necessary that the chambers be provided with exhaust means so that as pressure is directed into one chamber, the other is exhausted to the atmosphere. In this manner the cylinder may be readily moved back and forth relative to the housing. While the chambers may be alternately exhausted in any suitable manner, according to the present invention, itis preferred that the exhaust means be operated alternately by the control rod simultaneously with the opening and closing of the spaced channel ways 34-34, 3535. To accomplish this the control rod 30 is arranged so that it not only functions as a means to alternately control and direct fluid pressure into the chambers, but also cooperates with the piston rod to exhaust the chambers.

According to the present invention, this is accomplished by providing the piston rod with a pair of exhaust ports 40 and 41, each positioned closely adjacent the faces 26e of the piston head 26a. See Figs. 1 and 3. These exhaust ports 40 and 41 connect each chamber with the hollow interior portion of the piston rod.

At each end of the piston rod 2o there is provided transverse bores 42 and 43 which connect the hollow portion of the piston rod to the atmosphere. In the particular embodiment the end walls 12 and 13 of the housing are provided with an enlarged recess 12b and 13b so that the transverse bore communicates freely with the atmosphere.

In order to connect each pair of exhaust ports 40 and 41 with its respective transverse bore or outlets 42'and 43, thecontrol rod 3) is provided with a pair of longitudinal passageways 44 and 45 having at the inner end thereof vertical inlet exhaust ports 46 andV 47 which ports are adapted to be alternately aligned with ports 40 and 41'respectively, and transverse outlet ports 48 and 49 on the other end thereof to be alternately connected with the respective outlet ports 42 and 43. Thus, as shown in `Fig. l, when passageway 45 connects exhaust port 41 with outlet 43, the exhaust port 40 is closed. When the control bar is moved to the right, exhaust port 40 opens and port 41 closes.

Thus it is obvious from the drawings that as fluid pressure is being directed into one chamber, the exhaust means of the other chamber` is opened while the exhaust means of the said chamber under pressure is closed. Consequently, the pressure in the one chamber, being greater than that of the other, causes the cylinder to move in the direction in which the fluid pressure is supplied. As the cylinder approaches the end of its stroke, the end walls 23, 24 respectively engage the pin 38 to slide the control rod relative to thexed piston so that the fluid pressure is directed to the other chamber and the exhaust means of the other is opened. This cycle of operation is continued automatically as long as fluid pressure is directed into the cylinder, so that the latter and file secured thereto transverse a reciprocating power stroke.

From the foregoing description it will be noted that the length of stroke may be predeterminately positioned by varying the proportionate length of the cylinder to that of the housing.

The present invention, it will be noted, is simple in construction and has a minimum number of moving parts. As a result, much of the bulk and complexity which was an inherent disadvantage in the devices heretofore known is eliminated. The ball bearing sliding means between the housing and cylinder insure ease and smoothness of operation, while the pneumatic driving means insures 'a positive, high-speed operation of the device.

Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others.

I claim:

l. A power tool comprising a housing, a hollow piston rod connected in fixed relationship to said housing, said hollow piston rod having a piston head fixed thereto intermediate the ends thereof, a cylinder slidably mounted relative to said housing and rod connected thereto, said piston head dividing the cylinder into two chambers, and tluid means for reciprocating said cylinder relative to said housing, including a control means slidably disposed within said rod *and operatively associated with said piston rod to alternately control the ingress or egress vof an actuating iluid into and out of said chambers so that said cylinder transverses a working stroke.

2. A power tool of the character described comprising a housing having end walls, a cylinder slidably mounted on said housing so that the cylinder can reciprocate relative thereto, a tool connected to said cylinder to move therewith, a hollow piston rod extending through the ends of said cylinder and having the end portions thereof connected to said walls, said piston rod guiding the cylinder as it reciprocates, a piston head disposed intermediate the ends of the piston rod and ixed thereto, said piston head dividing the cylinder into two chambers, a control rod disposed within said piston rod, and fluid means for reciprocating said cylinder so that said cylinder and connected tool transverse a working stroke, said control rod having means to alternately control the ingress and egress of said fluid into and from said chambers to operate said cylinder.

3. A power tool of the character described comprising a housing having end walls, a cylinder slidably mounted on said housing so that the cylinder can reciprocate relative thereto, uid means for driving said cylinder, including a hollow piston rod extending through the ends of said cylinder and having the end portions thereof connected to said walls, said rod having a passageway adapted to connect to a source of fluid supply, a piston head disposed intermediate the ends of the piston rod and fixed thereto, said piston head dividing the cylinder into two chambers, said piston rod having an exhaust port on either side of the piston head, and a control rod disposed within said piston rod, said control rod having means cooperating with said exhaust ports to alternately control the ingress and egress of said fluid into and from said chambers, thereby causing the same to reciprocate relative to the housing.

4` A power tool comprising a housing `having end walls,

and two pairs of spaced exhaust ports, a piston head disi posed intermediate the ends of said piston. rod to divide said cylinder into two chambers, said piston head having an intake portion communicating with said supply passageway and spaced channel ways communicating with each or said chambers, a control rod slidably mounted within said hollow piston rod, said control rod having a pair of spaced longitudinal exhaust channels and a pair of transverse feed channels, and means for controlling said rod so that said transverse feed channels alternately connect said spaced channel ways of said piston head with said intake port to alternately direct iluid pressure into said chambers and said means alternately connecting said exhaust channels in said control rod with a pair of exhaust ports to exhaust one chamber as duid pressure is built up in the other, thereby causing said cylinder and connected tool to reciprocate.

5. A power tool comprising a housing having end walls, a cylinder slidably mounted on said housing so that said cylinder can reciprocate relative thereto, a working tool connected to said cylinder to move therewith and fluid means to prime said cylinder, said means including a hollow piston rod extending through the ends of said cylinder and having the end portions thereof connected to said walls, a piston head disposed intermediate the ends of said piston rod to divide said cylinder into two charnbers, said piston rod having means adapted to be connected to a source of supply and having a plurality of exhaust ports for venting said chambers to the atmosphere. said piston head having an intake port communicating with said supply means and spaced channel ways cornmunicating with each of said chambers, a control rod slidably'mounted within said hollow piston rod, said control rod having a pair of spaced longitudinal exhaust channels adapted to connect said exhaust ports and a pair oftransverse feed channels adapted to connect with said spaced channel ways, and means for controlling said rod so that said transverse feed channels alternately connect said spaced channel ways of said piston head with said intake port to alternately direct iluid pressure into said chambers and to alternately connect said exhaust channels in said control rod with a pair of said exhaust ports to exhaust one chamber as iluid pressure is built up in the other, thereby causing the said cylinder to reciprocate.

AReferences Cited in the file of this patent UNITED STATES PATENTS 2,255,395 Spink Sept. 9, 1941 

